Users can use database queries, for example, to access specific information in a database. For example, databases can be relational, hierarchical, in other forms or structures, and/or some combination thereof. Query languages can use standard commands, including structured query language commands that provide a level of abstraction and ease-of-use for users to identify the information to be queried. For example, users can enter and modify queries manually. Further, queries can be generated automatically based on user selections, e.g., from user interfaces that allow a user to identify particular fields and/or information to be displayed and conditions and/or parameters for identifying the information.
Some queries, depending on their scope and structure, can be quite complex. Further, some queries can become inefficient and/or may require a significant amount of execution time for the query to run. For example, some queries may perform JOINs of tables or other structures, and some query processing can result in large numbers of tuples of information being accessed, e.g., when Cartesian products occur. Other query inefficiencies may exist.